On the composition of oceanic and littoral manganese nodules (published online 2015)

The following analyses were made some years ago, principally with the object of ascertaining the state of oxidation of the manganese in the nodules. The nodules examined came from three different localities, two of them oceanic and the third littoral. Samples marked I., II., and III. are from nodules brought up in the trawl on board the "Challenger," on 13th March 1874, in lat. 42° 42' S., long. 134° 10' E. The depth of the water was 2600 fathoms, and the temperature of the bottom water 0·2° C. The density of the bottom water was 1·02570 at 15·56° C. Being from a high southern latitude, and therefore near the source of surface aeration, the water is highly charged with atmospheric gases, especially oxygen. It contained, per litre, 18·4 c.c. of mixed nitrogen and oxygen, of which 31·81 per cent, was oxygen, and 27·33 c.c, or 53·7 milligrammes, loosely-bound carbonic acid. The position of the station is about 400 miles south-west of the nearest part of the Australian coast, and about 500 miles west of Tasmania. It was the deepest water observed in the Antarctic voyage between the Cape of Good Hope and Melbourne. The haul was a very abundant one, and a few notes which I made at the time may be interesting: -"The water was found unexpectedly deep, the bottom being red clay, with some Foraminifera.

Chemical composition of Lake George (New York) iron-manganese nodules and underlying sediment

Lake George, New York, is the site of a new discovery of iron-manganese nodules. These nodules occur at a water depth between 21 and 36 m along a stretch of lake extending for about 5 mi north and south of the Narrows, a constricted island-dotted area which separates the north and south Lake George basins. Nodules occur on or within the uppermost 5 cm of a varved glacial clay. Some areas are solidly floored with a carpet of nodules in areas where active currents keep the nodules exposed. The nodules form around nuclei which consist of clay and less commonly of spore capsules, detrital particles, or bark. By their shape we recognize three types of nodules: spherical, discoidal, and lumps. On X-ray examination all nodules show small goethite peaks; in one nodule the manganese mineral birnessite was identified. Manganese and part of the iron appears to be in X-ray amorphous ferromanganese compounds. The Lake George nodules are enriched in iron with respect to marine nodules but are lower in manganese. They have a higher trace element concentration than nodules from other known freshwater lake occurrences, but a lower concentration than marine nodules.